FORD 2004 Expedition v.2 - Manual (Page 327)

increase in the contained air temperature. Contained air temperature is
dependent upon several factors such as rate of tire rotation, tire
deflection, amount of braking, etc. In similar manner, the tire pressure
will decrease if the contained air temperature decreases. For example, if
the vehicle is stationary over night with the outside temperature
significantly lower than the daytime temperature, the tire pressure may
decrease approximately 20.7 kPa (3 psi) for a drop of 16.6° C (30° F) in
ambient temperature. This lower pressure value may be detected by the
TPMS as being significantly lower than the cold pressure indicated on
your vehicles tire label, and activate the TPMS warning for low tire
pressure. If the low warning light is on, visually check each tire to verify
that no tire is flat. If one or more tires are flat, repair of fix as necessary.
If all tires appear to be inflated, carefully drive the vehicle to the nearest
location where air can be added to the tires. Turn the ignition to the
“off” position. Inflate all the tires to the recommended cold pressure.
The system uses radio-frequency to monitor the tire pressure on all tires
excluding the spare tire. The sensors transmit the tire pressure readings
to the receiver module located in the vehicle. The receiver module then
electronically transmits the status to the message center. For more tire
warning information, refer to the Message Center in the Driver controls
chapter.
This device complies with part 15 of the FCC rules and with RS-210 of
Industry Canada. Operation is subject to the following two conditions:
(1) This device may not cause harmful interference, and (2) This device
must accept any interference received, including interference that may
cause undesired operation.
The tire pressure monitoring system is NOT a substitute for
manually checking tire pressure. The tire pressure should be
checked periodically (at least monthly) using a tire gauge, see Tire
inflation pressure in this chapter. Failure to properly maintain your
tire pressure could increase the risk of tire failure, loss of control,
vehicle rollover and personal injury.
2004 Expedition (exd)
Owners Guide (post-2002-fmt)
USA English (fus)
Maintenance and Specifications
327